fix docker build
fix docker build

pool mysql-Connector! https://bugs.mysql.com/bug.php?id=79766

nicozhang/pyspider,qiulimao/weblocust,wangjun/pyspider,lashwang/pyspider,luoq/pyspider,snakeliwei/pyspider,wonderay/pyspider,luoq/pyspider,snakeliwei/pyspider,binux/pyspider,binux/pyspider,eromoe/pyspider,wangjun/pyspider,wonderay/pyspider,eromoe/pyspider,nicozhang/pyspider,eromoe/pyspider,snakeliwei/pyspider,wangjun/pyspider,qiulimao/weblocust,lashwang/pyspider,VDuda/pyspider,qiulimao/weblocust,lashwang/pyspider,wonderay/pyspider,VDuda/pyspider,binux/pyspider,VDuda/pyspider,luoq/pyspider,nicozhang/pyspider